I use to fly back and forth to Germany every two weeks and racked up at least a million miles. Aside from the baggage allowance it wasn’t worth bothering using miles. When I would try to use miles they sent me all over. One example was trying to fly from SFO to LAX. Seems easy since there are probably a hundred flights a day, right? BUT they wanted to make the route through Chicago, to Phoenix, and then finally LAX making a one hour flight a full day of travel. And in all thos years I only got the “free” upgrade once.